Surgical intervention at damaged or compromised bone sites has proven highly beneficial for patients, for example patients with back pain associated with vertebral damage. One of the most common types of damage, particularly in patients with osteoporosis, is associated with vertebral compression fractures (VCF).
Bones of the human skeletal system include mineralized tissue that can generally be categorized into two morphological groups: “cortical” bone and “cancellous” bone. Outer walls of all bones are composed of cortical bone, which has a dense, compact bone structure characterized by a microscopic porosity. Cancellous or “trabecular” bone forms the interior structure of bones. Cancellous bone is composed of a lattice of interconnected slender rods and plates known by the term “trabeculae.” Both structures may be weakened by osteoporosis, and compression fractures may occur that distort a vertebra (generally along its vertical axis), which can cause great pain.
During certain bone procedures, cancellous bone is supplemented by an injection of a palliative (or curative) material employed to stabilize the trabeculae. For example, superior and inferior vertebrae in the spine can be beneficially stabilized by the injection of an appropriate, curable material (e.g., PMMA or other bone cement). In other procedures, percutaneous injection of stabilization material into vertebral compression fractures by, for example, transpedicular or parapedicular approaches, has proven beneficial in relieving pain and stabilizing damaged bone sites. Other skeletal bones (e.g., the femur) can be treated in a similar fashion. In any regard, bone in general, and cancellous bone in particular, can be strengthened and stabilized by a palliative injection of bone-compatible material. Indeed, bone structure may be strengthened and at least partially restored (e.g., restoration of vertebral height/thickness previously lost to VCF) by these procedures. Exemplary devices and methods are summarized herein, and are disclosed in greater detail in U.S. Pat. Nos. 7,713,273; 7,799,035; 7,922,690; 8,021,037; 8,128,633; 8,226,657; and 8,277,506; as well as U.S. Pat. Publ. Nos. 2011/00044220; 2012/0239047; and 2012/0277753, each of which is incorporated herein by reference in its entirety (although, to the extent there is any discrepancy, the present disclosure shall prevail unless there is a clearer alternative).
The conventional technique for delivering the bone stabilizing material entails employment of a straight access device or cannula that bores (or otherwise cuts) through the cortical bone to gain access to the cancellous bone site. Bone stabilization material is then driven through the cannula to fill a portion of the cancellous bone at the bone site. As an intermediate step, a cavity may be created within the bone by inflating a balloon therein and/or by mechanically disrupting the bone by rotating a curved cannula. This may provide for greater penetration and stabilizing effect of the bone stabilization material. To minimize invasiveness of the procedure, the cannula is typically a small diameter needle.
With the above in mind, because the needle cannula interacts with the cancellous bone and other soft tissue structures, an inherent risk exists that following initial insertion, the needle cannula might core or puncture other tissue and/or the bone mass being repaired (at a location apart from the insertion site). Thus, during percutaneous vertebroplasty, great care must be taken to avoid puncturing, coring, or otherwise rupturing the vertebral body. Similar post-insertion coring concerns arise in other interior bone repair procedures. Along these same lines, to minimize trauma and time required to complete the procedure, it is desirable that only a single bone site insertion be performed. Unfortunately, for many procedures, the surgical site in question cannot be fully accessed using a conventional, straight needle cannula. For example, with vertebroplasty, the confined nature of the inner vertebral body oftentimes requires two or more insertions with the straight needle cannula at different vertebral approach locations (“bipedicular” technique). It would be desirable to provide a system for delivering bone stabilizing material that can more readily adopt to the anatomical requirements of a particular delivery site, for example a system capable of promoting unipedicular vertebroplasty.
Certain currently-available instruments utilize a curved needle to deliver bone stabilizing material as part of vertebroplasty or similar procedure. The curved needle purportedly enhances a surgeon's ability to locate and inject the stabilizing material at a desired site. Similar to a conventional straight needle cannula, the curved needle dispenses the curable material through a single, axial opening at the distal-most tip. However, the curved needle is used in combination with an outer cannula that assists in generally establishing access to the bone site as well as facilitating percutaneous delivery of the needle to the delivery site (within bone) in a desired fashion. More particularly, the outer cannula first gains access to the bone site, followed by distal sliding of the needle through the outer cannula.
These existing techniques have proven effective for treatment of certain VCF and other degenerative bone conditions. However, those bone conditions that may benefit from vertebroplasty and/or balloon-vertebroplasty (a/k/a “kyphoplasty”) can include other disease conditions. For example metastatic tumors (e.g., those originating from prostate cancer or another primary cancer location), benign tumors, and/or other tissue masses may occur within bone such as a vertebra and cause or co-exist with a fractured condition or other degenerative condition that could be benefited by treatment with bone-stabilization material. In the past, certain techniques would encapsulate such a tumor or tissue mass within the bone-stabilization material. Cryoablation has also been used, as has some application of radiofrequency (RF) ablation. For example, U.S. Pat. Publ. No. 2010/00211076 to Germain et al. discloses an RF ablation device that uses a segmented/linkage-curved needle electrode. However, existing needles may be limited with regard to manipulability and ease of use within intravertebral space.
A need exists for an improved device and system for ablating tissue within bone and/or other tissue sites in a targeted manner, and—if appropriate—thereafter delivering stabilizing material to those sites.